Electronic devices, such as laptop PCs, PDAs, and cellular phones, are equipped with antennas used for wireless communications with external devices. As development of multi-functional and compact electronic devices has progressed, antennas have to be more compact and have to support multiple frequency bands.
In this respect, a dual-band antenna is known. The dual-band antenna is equipped with a first antenna element of a folded monopole-type which is disposed between the feeding point and the ground point. The dual-band antenna is also equipped with a second antenna element branching off from the first antenna element at a point near the feeding point and extending separately from the first antenna element (see, for example, Japanese Patent Application Publication No. 2006-196994). This antenna supports two frequency bands as the first antenna element supports a first one of the two frequency bands and the second antenna element supports a second one of the two frequency bands. In addition, the impedance matching of the antenna with the transmitting and receiving circuits is accomplished by adjusting the shapes and dimensions of the first and the second antenna elements.
However, such a shape of the dual-band antenna—specifically, the shape with the second antenna element branching off from the first antenna element—makes it difficult to mount the antenna in a limited space.